Prostate cancer (CaP) is the most commonly diagnosed non-cutaneous cancer in men and a leading cause of morbidity and mortality. Androgens and the androgen receptor (AR) participate in the development of CaP. Androgen deprivation therapy (ADT), which suppresses testicular androgen production (via orchiectomy or luteinizing hormone-releasing hormone agonists), is the most effective systemic therapy for patients with hormone-sensitive CaP (HSPC). Ross et al., Cancer 112:1247-53 (2008); and Ross et al., J Clin Oncol. 26:842-847 (2008). Unfortunately, most HSPCs eventually become resistant to ADT and progress to castration resistant CaP (CRPC). CRPC proliferates despite castrate levels of serum testosterone and is usually fatal. Feldman and Feldman, Nat Rev Cancer 1, 34-45 (2001); Nelson et al., N Engl J Med. July 24; 349(4):366-81 (2003); and Scher and Sawyers, J Clin Oncol. 23:8253-8261 (2005). Thus, there is a need for methods in which response to ADT can be assessed.